Postharvest treatments to reduce chilling injury symptoms in stored ...

temperatures with one or more exposure to non-chilling (higher) temperatures.
Rewarming allows metabolism of the toxic products which accumulates in the tissues at
low temperature (Pentzer and Heinz, 1954) and also restores certain depleted essential
metabolites. Rewarming also allows the revival of oxidative phosphorylation in tissues as
it gets suppressed at low temperatures.
Temperature conditioning involves storage of products above the chilling
threshold temperature before they are stored at a low temperature (Wade, 1979). This
may be a single step operation or may be achieved in multi-steps by gradually decreasing
the temperature. However, a single step conditioning is less effective than a multi-step
conditioning.
Jacobi et al., (1995, 1996) reported that conditioning of mango fruit cv.
Kensington at 40°C increased heat tolerance and reduced the effect of heat injury.
According to these reports, those fruits which received HW conditioning treatment at 40
ºC for 8-12 h had minimum heat injury and showed internal and external cavities and
starchy layer beneath the skin. Heat-treatment effectively increases fruit heat tolerance
and reduces CI in stored avocado (Woolf et al., 1995). There are different techniques
which are used to minimize the incidence of CI.
2.5.1 Use of heat-treatment
Different heat-treatments have been used to alleviate the incidence of CI
symptoms in mango fruits. VHT-treated mango fruits showed increased level of
putrescine and its accumulation helped the reduction of CI (Esguera and Lizada, 1990).
As stated by González et al. (2000) peppers treated with HW at 53 °C for 4 min, had a
reduced incidence of CI after 14 and 28 days storage at 8 °C. It has been hypothesized
that HW-treated fruits show increased level of polyamine which reduces CI symptoms in
fruits (González, 1997).
Ethylene-treated fruits, irrespective of the method of application, cause severe
mesocarp discoloration in avocado fruits. Loss of green color has been observed in plant
tissues while they are treated with Ethylene. The treatment also decreases fruit firmness,
and CI during prolonged storage (Watada, 1986). The mechanism by which ethylene
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